Single \pi^- production in np collisions for excess energies up to 90 MeV

The COSY-TOF collaboration Abdel-Bary, M. ; Brinkmann, K. -Th. ; Clement, H. ; et al.
Eur.Phys.J.A 36 (2008) 7-16, 2008.
Inspire Record 759337 DOI 10.17182/hepdata.66229

The quasifree reaction $np\to pp\pim$ was studied in a kinematically complete experiment by bombarding a liquid hydrogen target with a deuteron beam of momentum 1.85 GeV/c and analyzing the data along the lines of the spectator model. In addition to the three charged ejectiles the spectator proton was also detected in the large-acceptance time-of-flight spectrometer COSY-TOF. It was identified by its momentum and flight direction thus yielding access to the Fermi motion of the bound neutron and to the effective neutron 4-momentum vector $\mathbb{P}_n$ which differed from event to event. A range of almost 90 MeV excess energy above threshold was covered. Energy dependent angular distributions, invariant mass spectra as well as fully covered Dalitz plots were deduced. Sizeable $pp$ FSI effects were found as were contributions of $p$ and $d$ partial waves. The behavior of the elementary cross section $\sigma_{01}$ close to threshold is discussed in view of new cross section data. In comparison with existing literature data the results provide a sensitive test of the spectator model.

4 data tables

Differential cross sections in $\mu b/sr$ for the angular distributions of the relative proton momentum at six excess energies Q.

Expansion coefficients of the Legendre polynomial fits to the angular distributions of the relative proton momentum.

Differential cross sections in $\mu b/sr$ for the angular distributions of the pion angular momentum at six excess energies Q.

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Differential cross sections measurement for the p p --> d pi+ reaction at 850-MeV/c.

The GEM collaboration Betigeri, M. ; Bojowald, J. ; Budzanowski, A. ; et al.
Phys.Rev.C 63 (2001) 044011, 2001.
Inspire Record 551879 DOI 10.17182/hepdata.54884

The present data support a large anisotropy in accordance with phase shift predictions and in contrast to another recent experiment.

4 data tables

Measured deuteron angular distribution in the c.m. system. The errors shown are statistical only and there is an additional 10 PCT systematic uncertainty on the overall normalisation.

Legendre polynomial coefficients from a second order and fourth order fit.

Total cross section from second order fit.

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Study of the reaction anti-p p ---> anti-Lambda Lambda at 1.546-GeV/c and 1.695-GeV/c

Barnes, P.D. ; Diebold, G. ; Franklin, G. ; et al.
Nucl.Phys.A 526 (1991) 575-601, 1991.
Inspire Record 301648 DOI 10.17182/hepdata.36756

The PS185 experiment at the CERN Low Energy Antiproton Ring (LEAR) has studied the reaction p ̄ p → \ ̄ gLΛ at several momenta. In this paper results from two runs with high statistics at 1.546 GeV/ c and 1.695 GeV/ c are described. Based on 4063 and 11362 analysed events, respectively, differential and integrated cross sections, polarizations and spin correlations are presented. The singlet fraction, extracted from the spin correlations, is consistent with zero at both momenta, showing that the \ ̄ gLΛ pairs are produced in a pure triplet state. A comparison of the decay asymmetry parameters of Λ and \ ̄ gL reduces the upper limits for the violation of the CP invariance for this system.

10 data tables

No description provided.

THE BESTFIT WITH LMAX=3, HI2=1.204.

THE BESTFIT WITH LMAX=6, HI2=0.547.

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Measurement of the Reaction $\bar{p} p \to \bar{\ell}$ambda Sigma0 + $c$.$c$. At 1.695-{GeV}/$c$

Barnes, P.D. ; Birien, P. ; Bonner, B.E. ; et al.
Phys.Lett.B 246 (1990) 273-277, 1990.
Inspire Record 295561 DOI 10.17182/hepdata.29675

The reaction p p → Λ Σ 0 together with its charge conjugate channel (c.c.) has been measured at LEAR. The incident p momentum was 1.695 GeV/ c , corresponding to an excess energy above threshold of 14.8 MeV. Results are given for the production cross section and the differential cross section as well as for the polarization. Comparisons are made with theoretical calculations and with the reaction p p → Λ Λ .

4 data tables

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Experimental Study of the Reactions $\bar{p} p \to \pi^- \pi^+$ and $K^- K^+$ Between 360-{MeV}/$c$ and 760-{MeV}/$c$

Tanimori, T. ; Ishimoto, S. ; Nakamura, K. ; et al.
Phys.Rev.D 41 (1990) 744, 1990.
Inspire Record 283782 DOI 10.17182/hepdata.22921

The folded differential cross sections dσdΩ(θ*)+dσdΩ(π−θ*), where θ* is the center-of-mass angle of the negatively charged outgoing particle, have been measured for the reactions p¯p→π−π+ and K−K+ at 15 incident beam momenta between 360 and 760 MeV/c with much better statistics than previous experiments. The total cross sections for these reactions, σπ−π+ and σκ−κ+, have also been obtained by integrating the folded differential cross sections. The folded differential cross sections of both reactions show a similar behavior at all measured beam momenta, characterized by a prominent peak at |cosθ*|=1. The cross section σπ−π+ shows a smooth but rapidly decreasing behavior as the beam momentum increases up to 550 MeV/c, whereas σκ−κ+ shows a smooth and flat momentum dependence. These results are compared with some theoretical calculations based on nonrelativistic quark models. Although the shape of the folded differential cross section of the p¯p→π−π+ reaction is rather well reproduced by these models, that of the p¯p→K−K+ reaction, and, in particular, the prominent peak at |cosθ*|=1 cannot be explained at all. The information from other experiments indicates that this discrepancy is most pronounced at the backward angles. Moreover, the momentum dependence of both σπ−π+ and σκ−κ+ is not satisfactorily reproduced by these models.

33 data tables

Folded differential cross sections.

Folded differential cross sections.

Folded differential cross sections.

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Measurement of $d \sigma / d \Omega$ and A(on) in $\bar{p} p$ Elastic Scattering Between 497-{MeV}/$c$ and 1550-{MeV}/$c$

Kunne, R.A. ; Beard, C.I. ; Birsa, R. ; et al.
Nucl.Phys.B 323 (1989) 1-36, 1989.
Inspire Record 267175 DOI 10.17182/hepdata.48676

Measurements have been made of the differential cross section and asymmetry A on for p p elastic scattering at 15 incident momenta between 497 MeV/ c and 1550 MeV/ c . The angular range where both particles have enough energy to traverse target and setup has been covered. The results are compared with predictions of various N N potential models. None of these models fully explains the present results, although the general trend of the data is predicted correctly.

16 data tables

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Differential Cross-Sections for K- p Elastic Scattering from 1.4-GeV/c to 1.9-GeV/c

Abe, K. ; Barnett, B.A. ; Goldman, J.H. ; et al.
Phys.Rev.D 12 (1975) 6-14, 1975.
Inspire Record 103522 DOI 10.17182/hepdata.24826

We report here the results from an experiment to obtain differential cross sections for K−p elastic scattering in the laboratory momentum region from 1.4 to 1.9 GeV/c. These data span the region of a bump in the K−p total cross section at an energy of 2.05 GeV. Approximately 20000 elastic events were obtained at each of four momenta with an angular coverage of 0.9≥cosθc.m.≥−0.9. The data are intended to aid in phase-shift analyses of the resonances causing the bump in the total cross section and to study dip structures at constant values of the Mandelstam variables t and u.

3 data tables

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LEGENDRE POLYNOMIAL COEFFICIENTS.

FROM INTEGRATING LEGENDRE POLYNOMIAL FIT TO D(SIG)/DOMEGA. QUOTED ERRORS INCLUDE NORMALIZATION AND FITTING UNCERTAINTIES.


DIFFERENTIAL CROSS-SECTIONS FOR K+ p ELASTIC SCATTERING FROM 0.865-GeV/c TO 2.125-GeV/c: DATA LISTING

Abe, K. ; Barnett, B.A. ; Goldman, J.H. ; et al.
Phys.Rev.D 11 (1975) 1719-1732, 1975.
Inspire Record 81409 DOI 10.17182/hepdata.4763

We report on an experiment to obtain differential cross sections for K+p elastic scattering in the vicinity of the possible exotic baryon, the Z1*(1900). The differential cross sections are based on typically 70 000 selected events in the angular region −0.9≤cosθc.m.≤0.9 at each of 22 momenta from 0.865 to 2.125 GeV/c. The data are intended for use in partial-wave analysis to search for the Z1*.

26 data tables

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Differential cross sections for elastic pi+ p scattering between 1.2 and 2.3 GeV/c

Abe, K. ; Barnett, B.A. ; Goldman, J.H. ; et al.
Phys.Rev.D 10 (1974) 3556-3572, 1974.
Inspire Record 97248 DOI 10.17182/hepdata.238

Differential cross sections for π+p elastic scattering in the momentum region 1.2 to 2.3 GeV/c are presented for the center-of-mass angular range 0.9>cosθ>−0.9. Typically, 50 000 events were obtained at each of 16 momenta using magnetostrictive-readout wire spark chambers to detect the particles scattered from a liquid hydrogen target. The results are compared to those of the CERN-71 phase-shift analysis. The well-known dips at t≅−0.7 (GeV/c)2 and at u′=−0.2 (GeV/c)2 are observed. In addition, structure is seen at constant u′=−1.3 (GeV/c)2. The results of a pion attenuation study in iron are also presented.

18 data tables

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